432 CONDITIONS INFLUENCING TEMPERATURE OF ORGANS. 



210. Conditions influencing the Temperature 



of Organs. 



The temperature of the individual organs is by no means constant; 

 it is influenced by many conditions; amongst these are the following: 



(1.) The more heat that is produced independently within a part, the 

 higher is its temperature. As the amount of heat produced within a part 

 depends upon its metabolism, therefore, when the metabolism is in- 

 creased, the amount of heat produced is similarly increased. 



(a) Glands produce more heat during the act of secretion, as is proved 

 by the higher temperature of their secretion, or by the higher tempera- 

 ture of the venous blood flowing out of their veins. Ludwig found 

 that when he stimulated the chorda tympani, the secretion of the sub- 

 maxillary gland was l'5C. warmer than the blood in the carotid, which 

 supplied the gland with blood. The blood in the renal vein in a 

 kidney which is secreting is warmer than the blood in the renal artery. 

 The secreting liver produces much heat. Cl. Bernard investigated the 

 temperature of the blood of the portal and hepatic veins during hunger, 

 at the beginning of digestion, and when digestion was most active, and 

 he found : 



Temperature of portal vein, . 37'8C. 1 After 4 days / Blood of right heart, 

 hepatic ,, .38*4 J starvation. \ 38 '8. 



(Hunger period.) 



: 81 ! Begins of digestion.' 



Temperature of portal vein, . 39 '7 ) Digestion most / Blood of right heart 

 ,, hepatic, . 41 '3 \ active. \ during digestion, 39 - 2. 



When a dog receives a moderate diet, the mean temperature in the stomach is 

 39C., in the rectum, 39'5C.; at the end of the first day of hunger, in the stomach, 

 387, in the rectum, 39'3; while after food, in both situations it is 40. 

 Chemical or mechanical stimulation of the gastric mucous membrane, or even the 

 sight of food, has a similar action (Kronecker and Meyer). 



(&) When the muscles contract they evolve heat (Bunsen, 1805). 

 Davy found that an active muscle became 0'7C. warmer; while 

 Becquerel (1835), by means of a thermo-galvanometer, found that 

 human muscles, when kept contracted for five minutes, became 1C. 

 warmer (see Physiology of Muscle). 



This is one of the reasons why the temperature may rise above 40 during 

 rapid running. A temperature obtained by energetic muscular action usually does 

 not fall to the normal until after resting for H hours (Billroth). The low 

 temperature of paralysed limbs depends partly upon the absence of the muscular 

 contractions. 



(c) With regard to the effect of sensory nerves upon the tempera- 



